clear-all

a command that:

• sets all the code-defined (not slider defined) global variables to zero
• clears the tick counter (leaving it with no value, not zero)
• kills all the turtles
• resets all the patch variables (including color) to their defaults
• clears all the all lines and stamps drawn by turtles
• clears every plot
• clears the text from the model output area (if applicable)